Such a closing apparatus is known from U.S. Pat. No. 3,717,972. Both the punch and a double-acting cam plate for swiveling the two constricting arms serving as constricting components are fastened on the piston of a pneumatic cylinder. When the pneumatic cylinder is actuated, the cam plate initially swivels the constricting arms, which form a braid of the packaging tube (which is initially elongated in its cross-section). At the same time, appropriately designed sections of the constricting arms extend the guidance provided in the carrier for the punch, so that in the closed state of the constricting arms, this guidance extends to the matrix that is arranged in one of the constricting arms and the punch can close the closure clip guided by it around the braid of the packaging tube with the help of the matrix during an additional operating stroke of the pneumatic cylinder.
Such closing apparatuses are employed in particular on machines for stuffing large-sized individual sausages. They are arranged in front of the end of the stuffing tube, wherein the respective stuffing tube can be part of a multiple stuffing head so that during the stuffing process of a sausage, the tubular casing for the next sausage that is to be stuffed can be pulled onto a different similar stuffing tube. Although the processing speed of such stuffing processes is not even close to that of modern stuffing, portioning and closing machines for the production of strings of subsequent sausages, the time factor and the mechanical load of the packaging tube play a considerable role. Additionally there is the desire to keep the apparatus-related and operational efforts, in particular also the wear of the closing apparatus, as low as possible.